1. Field of the Invention..
This invention pertains to fluid handling, and more particularly to apparatus for pumping high viscosity liquids.
2. Description of the Prior Art
Various equipment has been developed to spray liquids. For example, equipment for spraying coatings such as paint, lacquer, and anti-rust compounds is well known. Such coatings usually have relatively low viscosities, and conventional airless pumping units that operate on a hydraulic ram principle are entirely satisfactory.
However, such pumping units are not acceptable for spraying thick viscous liquids such as stripper materials. One well known grade of stripper has a viscosity of approximately 100,000 SSU, which is the consistency of lard. Although airless pumping units are occasionally used to spray viscous strippers, such use is a misapplication of the equipment. That is primarily because the units must be operated at pressures as high as 1000 PSI and even 3,000 PSI to enable them to pump the thick stripper. At such high pressures, there is great danger of a leak occurring somewhere in the system. The resulting jet of high pressure caustic material is extremely dangerous to nearby personnel. Further, the air compressor or five-to-one or ten-to-one pressure pump required to produce the necessary high pressures is expensive, thereby increasing capital expenditures. In addition, such high pressure machinery is bulky and cumbersome to work around at the job site.
There are pumps that transfer viscous fluids but not in a spray pattern. Pumps that do not create enough pressure produce a spray pattern that would be of no value when applying viscous paint strippers to an overhead or vertical surface.
Thus, a need exists for improved apparatus for spraying high viscosity liquids.